1. The problem statement, all variables and given/known data There are four wires viewed end-on in the drawing. They are long, straight, and perpendicular to the plane of the paper. Their cross sections lie at the corners of a square. Currents of the same magnitude are in each of these wires. Choose the direction of the current for each wire, so that when any single current is turned off, the total magnetic field at point P is directed towards corner of the square. 2. Relevant equations 3. The attempt at a solution I know that using the right hand rule by curling your fingers in the direction of the current you can find the direction of the magnetic field, but I don't think I am applying the rule right and I'm not sure how to get it so that if you turn a current off P always points to a corner. Can anybody help?